Coaches' Corner for Robofest 2006

This is an area where I will pass along tips for preparing for
the Robofest 2006 competition. The ideas, problems and
solutions presented here are things I learned while working
with other coaches. Your contributions or questions are always
welcome.

After a robot finds a pop bottle, it has to push the bottle
off the edge of the playing surface. If the robot is
watching a touch sensor attached to the bumper used to push
the bottle, there may be a problem maintaining consistent contact with the somewhat bouncy
bottles. If, when the robot's bumper loses contact with the
bottle, the robot rechecks about a half second later; then, the
robot can be reasonably sure the bottle is gone. In NQC

int sure = false;
...
until (sure == true) { // Keep on pushing until sure the bottle is gone.
if (TOUCH == 0) { // Sure if gone twice in a row with a half second
Wait(50); // between checks.
if (TOUCH == 0) sure = true;
}
}
// bottle is gone now. So, continue with the next part of the mission.

These three pictures show a hardware solution to de-bouncing
the pop bottle touch sensor. In this case the touch sensor
button is not depressed by pushing with a lever, but by
sliding an arm over the button from the side, which keeps it
depressed as long as the bottle is somewhere nearby. The
elastic band should be twisted to get the desired tension,
and held in place by 2 of the small circular white plates
that fit on top of an axle stub. The plates were removed
for these pictures.